Metal Nanoparticles

Manganese zinc ferrite is a complex metal oxide composed of oxides of manganese (Mn), zinc (Zn), and iron (Fe). It has a spinel structure and its chemical formula is usually represented as (Zn,Mn)Fe₂O₄.

DMSA Coated Fe₂O₃ Nanoparticles (Carboxylated ferric oxide nanoparticles) are magnetic nanomaterials with carboxyl (-COOH) groups modified on their surface. These materials typically consist of ferric oxide (Fe₂O₃) nanoparticles as a core, with carboxyl functional groups introduced to the surface through chemical modification. The carboxylation of the nanoparticle surface increases its negative surface charge, contributing to improved solubility and stability in water. Carboxylated ferric oxide nanoparticles exhibit good biocompatibility, making them suitable for biomedical applications.

Ultra-small magnetic iron oxide nanoparticles refer to iron oxide (Fe₃O₄) nanoparticles with very small size. These nanoparticles typically have a diameter of less than 10 nanometers (<10 nm), and the size observed by TEM is usually in the range of 5-10 nm.

PEGylated iron oxide nanoparticles (amino-terminated) are prepared by high-temperature pyrolysis and modified with PEG-amino-terminated oleic acid-modified iron oxide. This modification transforms the nanoparticles from the oil phase to the aqueous phase, thereby broadening their application in the biological field.

Due to their unique physical and chemical properties, noble metal nanoparticles, represented by platinum, gold, silver, and palladium, have been extensively studied by many scientists. Palladium is a noble metal belonging to the platinum group elements. Its elemental form is a silvery-white transition metal, soft in texture and possessing good ductility and malleability. Palladium nanoparticles, due to their unique physical, chemical, and electronic properties, have shown remarkable application potential in multiple fields. PEI surface modification of palladium nanoparticles can significantly improve their dispersibility, stability, and biocompatibility, and facilitate further coupling with other biomolecules or fluorescent molecules.

Due to their unique physical and chemical properties, noble metal nanoparticles, represented by platinum, gold, silver, and palladium, have been extensively studied by many scientists. Palladium is a noble metal belonging to the platinum group elements. Its elemental form is a silvery-white transition metal, soft in texture and possessing good ductility and malleability. Palladium nanoparticles, due to their unique physical, chemical, and electronic properties, have shown remarkable application potential in multiple fields. Surface modification of palladium nanoparticles with sodium citrate can significantly improve their dispersibility, stability, and biocompatibility, and facilitate further coupling with other biomolecules or fluorescent molecules.

Selenium (Se) is an essential trace element for the human body, playing a vital role in various physiological activities. In the body, selenium is bound to selenocysteine, an amino acid used to synthesize several selenoproteins. Selenium is often the active site of these proteins, playing a crucial role in maintaining intracellular redox balance. Chitosan-stabilized selenium nanoparticles (CS-SeNPs) are nanomaterials using the biopolymer chitosan (CS) as a stabilizer. Through electrostatic interactions, chitosan coats the surface of selenium nanoparticles (Se NPs), improving their dispersibility, stability, and biocompatibility. Se NPs themselves are characterized by low toxicity and high bioactivity, and the introduction of chitosan further enhances their functionality and application potential, making them widely recognized in biomedicine, food, and agriculture.

Silver nanoclusters (AgNCs) are ultrasmall nanoparticles composed of several to tens of silver atoms. Their size is close to the Fermi wavelength of electrons, thus exhibiting unique molecular-like properties, such as strong fluorescence. Silver nanoclusters possess small size, low toxicity, excellent photostability, large Stokes shift, and good biocompatibility. Lipoic acid (also known as octylsulfonic acid) acts as a ligand in the synthesis of silver nanoclusters, primarily playing a role in stabilizing and protecting the silver nanoclusters. The ligand binds to silver atoms through its specific chemical structure, forming a stable nanocluster structure and influencing the physicochemical properties of the clusters, such as fluorescence performance, catalytic activity, and biocompatibility. This demonstrates potential application value in various fields such as chemical analysis, biosensing, catalysis, medicine, and bioimaging.

Citrate-modified ferric oxide nanoparticles are functionalized nanoparticles formed by attaching citric acid to the surface of Fe₃O₄ nanoparticles. Due to their excellent biocompatibility and stability, Citrate-modified ferric oxide nanoparticles can be used as drug carriers for drug delivery and contrast enhancement in magnetic resonance imaging (MRI).

Carboxylated magnetic microspheres (low nonspecificity) are functionalized nano- or micron-sized magnetic particles with abundant carboxyl functional groups on their surface. Special chemical treatments reduce the likelihood of nonspecific adsorption. This 1μm carboxylated magnetic microsphere features a core-shell structure: a PS core, an outer layer of iron oxide (Fe₃O₄), and an outermost encapsulation layer. The carboxyl groups are obtained through polymer modification. Exhibiting low nonspecific adsorption, these microspheres can covalently couple with bioligands such as peptides, proteins, antibodies, and oligonucleotides using specific chemical reagents (e.g., EDC), making them particularly suitable for cell sorting, affinity chromatography, and immunoassay.

Monodisperse Fe₃O₄ microspheres (Monodisperse iron oxide microspheres) are microspheres composed of magnetic materials, with iron oxide as the main component. These microspheres are very uniform in size and exhibit monodispersity, meaning that the sizes of the microspheres are very similar with minimal differences.

Titanium dioxide magnetic beads are magnetic microparticle carriers whose surface is coated with titanium dioxide nanoparticles. This material is commonly used in protein digests of biological samples for the simple, convenient, efficient, highly specific, and reproducible enrichment of phosphorylated peptides. The surface properties of titanium dioxide magnetic beads make them show no significant preference for monophosphorylated or polyphosphorylated peptides, making them ideal for single-step enrichment of phosphorylated peptides in mass spectrometry-based proteomics analysis.

Carboxylated magnetic microspheres are magnetic microspheres with abundant carboxyl functional groups on their surface. They are usually composed of superparamagnetic materials (such as Fe₃O₄) and polymer materials, with polystyrene microspheres as the core.

Nanomaterials with sizes ranging from 1 to 100 nm are generally referred to as nanocrystals. The preparation of platinum nanocrystals with controllable morphology was first reported in 1996. Pt, Ag, Au, Rh, and other nanocrystals have been synthesized using various methods. Platinum has a face-centered cubic (fcc) structure, but unlike Ag, Au, and Pd, it rarely forms twins; most platinum nanocrystals are single-crystal structures. XFJ116 platinum nanoparticles were prepared via a chemical reduction method, exhibiting uniform size and good dispersibility, and can also provide platinum nanoparticles with amino and carboxyl terminator modifications.

APTS Fe₂O₃ Nanoparticles (Aminated ferric oxide magnetic nanoparticles) are magnetic nanomaterials modified with amino functional groups using APTS. This material consists of a ferric oxide (Fe₃O₄) nanoparticle core and an amino (-NH2) surface modification layer. The aminated surface helps improve the biocompatibility of the nanoparticles and reduce cytotoxicity. The amino functional groups can be further chemically modified for coupling with biomolecules such as drugs, proteins, and nucleic acids. The amino functional groups undergo protonation at different pH values, resulting in different surface charges on the nanoparticles in different pH environments.

Carboxymethyl dextran-modified iron(III) oxide nanoparticles are composite materials in which carboxymethyl dextran (CMD) is introduced onto the surface of iron(III) oxide (Fe₃O₄) nanoparticles through chemical modification. Carboxymethyl dextran is a water-soluble polysaccharide; its hydrophilicity and biocompatibility are enhanced by converting the hydroxyl groups of the dextran into carboxymethyl groups (-COOH).

Reactive oxygen species responsive hydrogels are a novel class of smart hydrogels, formed by the cross-linking of ROS-responsive modules through covalent, coordination, or supramolecular interactions. Due to the introduction of these ROS-responsive modules, these hydrogels exhibit a sensitive response to the oxidative stress microenvironment present in organisms. PVA-TSPBA hydrogel is a hydrogel formed by the cross-linking polymerization of polyvinyl alcohol (PVA) and the reactive oxygen species-sensitive cross-linking agent N1-(4-benzyl borate)-N3-(4-phenyl borate)N1,N1,N3,N3-tetramethyl-1,3-propanediamine (TSPBA). This hydrogel consists of two parts: a boric acid precursor (TSPBA) and an aqueous solution of PVA. The boric acid bonds on TSPBA and the hydroxyl groups on PVA rapidly cross-link to form borate ester bonds, thus forming the hydrogel.

Thiol-modified magnetite nanoparticles are prepared via high-temperature pyrolysis and surface-modified with thiol functional groups. Magnetite is widely used in magnetic resonance imaging, magnetic separation, targeted drug delivery, tumor hyperthermia, cell labeling and separation, as a contrast agent, and in retinal detachment repair surgery due to its stable properties, good biocompatibility, high strength, and lack of toxicity. It is also used as a catalyst carrier, microwave absorbing material, and magnetic recording material. Xianfeng has developed numerous derivatives of magnetite, including oleic acid-modified magnetite, magnetite with different PEG ends, DMSA-modified magnetite, polylysine-modified magnetite, carboxylated dextran-modified magnetite nanoparticles, streptavidin-modified magnetite particles, thiol-modified magnetite magnetic nanoparticles, and polyethyleneimine (PEI)-modified magnetic magnetite nanoparticles, among others.

Polyethyleneimine (PEI)-modified magnetic iron(III) oxide (Fe₃O₄) nanoparticles are a composite nanomaterial that combines the properties of magnetic nanoparticles and polyethyleneimine. Polyethyleneimine is a highly branched polymer with a high density of amino groups. These amino groups stabilize the Fe₃O₄ nanoparticles and provide sites for further functionalization. The amino groups of PEI impart a high surface positive charge to the Fe₃O₄ nanoparticles, which helps enhance their interaction with negatively charged cell membranes.